Hot water heater high temp button continues to trip. Changed both heating elements, both thermostats (upper one twice) continues to trip. Verified 120 volts on both incoming red and black wires and properly grounded.

Hot water heater high temp button continues to trip. Changed both heating elements, both thermostats (upper one twice) continues to trip. Verified 120 volts on both incoming red and black wires and properly grounded.

Make sure you have 220 volts or so between the two 120 volt legs. It is possible you have wired the unit incorrectly. While you were changing out thermostats for example because if the unit is wired correctly it will not trip the red high temp safety unless one of the thermostats is not wired correctly or the thermostat itself is defective.